Hot air furnace



pr M, W41.. R. JOVANOVITZ HOT AIR FURNACE Filed June l. 1939 Mmmm mul INVENTR. @aou- Janeway/rz if. t.

ATTORNEYS..

Patented Apr. 15, 1941 UNITED 'STATES PATENT OFM-CE HOT AIR FURNACE Rudolf J ovanovitz, St. Bernard, Ohio Application June 1, 1939, SeraLNaZVBZS 5 Claims.

My invention relates to heating ,furnaces and particularly to furnaces :for :domestici heating plants wherein there is a combined gravity flow and :forced air circulation.

In :the art fit is old yin domestic heating plants `to `have a return duct for cold air fromxthe .building, which duct .isdivided into 4a gravity flow conduit `and :a `forced air ,conduit `by-which the `air to be reheated and :recirculated fis combined and flows yinto the shell of the 'furnace `around the fire .pot where, after `it is heated, ,the warm air `rises through the various ducts to the `heat outlets `within `the building.

As far as I am advised, such combinations of `gravity return flow withforced .air return ,flow

`have `as :a disadvantage aiwidelyyariable iiow of air so that lwhen `.the blower or ffan forcing the draft is in operation, :too `much air `is 4caused to flowand `when the blower or fan is cut off, there is too ,little circulation of lair.

It is an `object .of my invention :to provide .la system for combined gravity .flowandforced `air `circulation ,Lin a heating plant wherein `variations in ithe flow of heated lair can be regulated within much more restricted variation of air circulation :than has heretofore `been possible.

It is specifically an object of my `invention to combine a forced air circulation with a gravity ow circulation wherein the `forced airis induced zthrough an elongated jet which causes the forced `air to exert `a syphon :effect which carries with `it :adesired iiow of Aair which `doesinot` pass through the blower. f f

.It isa further .object of Iny invention to so distribute the flow of induced air that it will be injected into the casing surrounding the fire pot of `the furnace in a continuous flow without eddy currents in which condition it .exerts a substanltia'lly constant pull on the intake from the gravity air `duct so as `to provide ,a well regulated flow of `air. i l The above objects and :other specific `objects in design `and arrangement `of the mechanical parts `employed which `will be later described, I accomplish by that certain combination and arrangement of parts of which I have shown a preferred modification which represents theinstallation in my own home where I have observed the many advantages and improvements of the particular system described.

Referring to the drawing:

Figure 1 is a side elevation of a preferred system.

preferred construction of elongated jet injector.

Figure 2 is a detail perspective view showing my Figure )3 is a detail plan view of the jet illus- `trated in Figure 2 taken along the `line 3 3 of Figurel.

Figure`4 is a sectional view taken along the 'line 4 4 of Figure l.

The furnace has an outer shell I which surrounds the `re `pot 2 within which the fuel is burned to heat the lire pot. There `is a `chamber 3 between the re pot and .the .outer shell ofthe furnace within which air currents are Aheated by the rfire pot and `rise through conduits such as yare indicatedat 4 trom which `they are discharged through warm air registers as indicated ,at `5 to heat the air within the building. 'The return flow of air from the building passes through a grille ,6 to the casing I. The casing is in the form of ametal box of enlarged cross sectional area as illustrated. From the base of the casing, a conduit 8 extends ldown vertically to a position where it is connected to the jet mixer generally indicated at 9. V

The casingl has a conduit Iii connected thereto which conduit has an end II which extends up to close proximity tothe top of the casing 'I so that the warmer air currents returning through the grille 6 are drawn into the vinduced air system.

'The conduit III is subdivided into two branch conduits It, as indicated in Figure 4, and I have shown a blower I3 having inlets It for the air which comes from the right hand conduit I2 and inlet I5 for the air which cornes from the left 'hand conduit-.12.

The blowermay be operated by moans of a motor AIl and pulley drive I'I.

The conduits I2 discharge into a hollow boxlike casing I 8 subdivided into two compartments by the wall I9.

The dischargefroin the blower passes through a conduit 2U preferably having a damper 2l therein, and is connected tothe jet vmixer While I have referred to the apparatus indicated at 9 as a jetmixer, I do Ynot thereby wish to be restricted to the `general class of jet mixers such as are known in V,this art. The term jet mixer is a convenientdescription zfor` the assemvbly ,indicated by the combination of `parts El whetheror not the ,factionof this mechanism is in accordance with the well known principle of jet propulsion.

The mixer 9 has a wide and shallow duct 22 through which the induced air is driven from the blower I3. A ilange 23 is bolted to the furnace and extending beyond the plane of contact of the ange I have shown an upwardly extending lip 24 or plate which I find of considerable utility in connection with causing an even flow of air.

The upper portion of the apparatus S consists of a wide and shallow duct 25 through which gravity air flows or is drawn depending on the operation of the blower.

In the casing I8 I preferably install a spun glass lter 26 through which the air passing down through the conduits I2' is filtered before being drawn into the blower.

In ordinary operation when the requirements for heated air are low, the motor I6 and blower I3 are not in operation, and descending cool air from the building passes down through the duct 3 through the conduit 25 into the space 3 surrounding the re pot where it is warmed and passes up through the conduits 4. When there are greater requirements for heated air, ordinarily controlled by means of a thermostat within the building, the

electrical controls for the motor I6 are closed so :2,

that the motor is started up and air is then drawn down through the conduit IU and the branch conduits l2 and ejected in a continuously moving current through the conduit 2.2. The eddy currents caused by the upwardly extending plate 24 cause a suction of air to be drawn in through the conduit 25 from the gravity return flow system and the amount of air forced into the space 3 is moderately increased.

I nd that the quantity of air passing down through the gravity flow system is substantially increased over the quantity of air which flows down through the conduit 8 when the blower is not in operation.

I nd that I provide a sort of jet injector effect 7 so that by a moderate flow of injected air, I substantially increase the flow of the combined injected and the gravity supply.

As typical dimensions of the conduit 22 at its discharge end into the furnace, I have found that dimensions of 3 inches in height by substantially 30 inches in width provide a satisfactory operation.

I of course do not wish to be limited to the specific dimensions shown inasmuch as variations in size and dimensions will readily occur to those skilled in the art to accommodate my system for smaller or larger heating plants.

I have shown my system of combining gravity iiow and forced air circulation in combination with a heating furnace, but it should be understood that in the summertime when it is desired to employ the heating system as a cooling system, that refrigerating apparatus may be substituted for the fire pot 2 so that my invention in its broader aspects consists in providing suitable apparatus and a system of controlling the ow of gases to equipment which is to condition the air either by warming it or cooling it.

With air cooling apparatus, such as that to which I have referred, ordinarily the conduits through which cooled air passes to the building have forced air circulation between the delivery conduits and the chamber in which the air is cooled, which is created by a fan or blower. This is because cool air will not rise.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a combined gravity flow and forced air circulation system in combination with a chamber wherein the air is conditioned for circulation in a building, a casing of enlarged cross sectional area supplied with returning air currents, a grille above said casing through which said currents pass, a conduit for gravity flow air connected to the bottom of said casing, and a suction conduit for forced air connected with its intake at the top of said casing at a position removed from said grille, said suction conduit branching into two conduits, and each of said conduits connected to the intake of a blower having a single discharge conduit into said chamber.

2. A forced air injector for a hot air furnace comprising a conduit having a wall dividing said conduit into an upper and a lower conduit, said upper conduit for natural draft air and said lower conduit for air under superatmospheric pressure, said lower conduit at its discharge end having a width approximately ten times its depth, and having a cross sectional area substantially half the area of the upper conduit.

3. A forced air injector for a hot air furnace comprising a conduit having a wall dividing said conduit into an upper and a lower conduit, said upper conduit for natural draft air and said lower conduit for air under superatmospheric pressure, said lower conduit at its discharge end having a width approximately ten times its depth, and having a cross sectional area substantially half the area of the upper conduit, and a baie extending beyond the discharge end of said dividing wall and inclined upwardly.

4. A forced air injector for a hot air furnace comprising a conduit having a wall dividing said conduit into an upper and a lower conduit, said upper conduit for natural draft air and said lower conduit for air under superatmospheric pressure, said lower conduit at its discharge end having a width approximately ten times its depth, and having a cross sectional area substantially half the area of the upper conduit, a baiile extending beyond the discharge end of said dividing wall and inclined upwardly, and means for inducing a steady non-eddying current of air through said lower conduit.

5. A combined gravity flow and forced air circulation system in combination with a chamber wherein the air is conditioned for circulation in a building, comprising in combination with a grille, a casing of enlarged cross sectional area through which air currents are drawn, a conduit of reduced cross sectional area extended from the bottom of said casing through which a gravity ow of air passes, a wide shallow conduit connected to said conduit of reduced cross section and through which a gravity flow of air passes into said chamber, a second wide shallow conduit below said rst noted conduit through which forced air currents pass to said chamber, a suction conduit extending into the upper part of said casing at one end and connecting with said second shallow conduit at its other end, and air impelling means in said conduit.

RUDOLF JOVANOVITZ. 

